高回收率反渗透海水淡化工艺

SEAWATER DESALINATION WITH HIGH RECOVERY RATE BY INTEGRATED MEMBRANE DESALINATION PROCESS

目前反渗透海水淡化的回收率小于40%。本文研究开发死端超滤预处理技术和反渗透-纳滤联合脱盐相结合的膜集成海水淡化新工艺,与传统工艺比较,具有装置体积小,产水回收率高等优点。文章介绍了采用新工艺的海水淡化装置样机的试制情况及现场运行结果。沿岸海水为料液,操作压力1为5.1MPa条件下,操作压力2为2.0MPa条件下,装置脱盐率99.21%,产水量397.3L/h,产水回收率55%。海水淡化装置对海水中Ca2+、Mg2+、Na+、HCO3-、Cl-、SO42-、TDS,总碱度,总硬度的脱除率分别为99%,99.6%,99.21%,95%,99.35%,98.48%,99.21%,95%,99.42%。

The fresh water recovery is restricted by the osmotic pressure in the process of the seawater desalination with reverse osmosis system. In general, the fresh water recovery rate would not exceed 40%. In this study, a new process for seawater desalination, integrated membranes desalination( IMD) process is developed by us. This process includes dead-end ultrafiltration for raw seawater pretreatment and reverse osmosis-nanofiltration for seawater desalination. In comparison with the traditional one pass RO seawater desalination process, the fresh water recovery of IMD process is higher and the size of the plant is less. A mobile seawater desalination plant is installed on a truck and it is operated at a seawater desalination site in Zhoushan, Zhejiang Province. The results showed that the desalination device's capacity was 397.3L/h, salt rejection was 99.21%, and the fresh water recovery rate was 55%, when feed was seawater, operating pressure 1was 5.1MPa, operating pressure 2 is 2.0 MPa. The IMD process could remove Ca2+?Mg2+?Na+?HCO3-?Cl-?SO42-?TDS, total basicity, total hardness from feed seawater and their removal rate were 99%, 99.6%, 99.21%, 95%, 99.35%, 98.48%, 99.21%, 95%, and 99.42% respectively. When feeding seawater concentration was 40177.91mg/L, the plant fresh water recovery rate reached to 49.75% and the brine concentration was 80788.96 mg/L.